Framing in construction includes vertical and horizontal members of exterior walls and interior partitions, both of bearing walls and non-bearing walls. These members, referred to as studs or stick members, wall plates (top and bottom) and lintels (headers), serve as a nailing (or other fastener) base for all covering material and support upper floor platforms, which provide lateral strength along a wall. The platforms may be the boxed structure of a ceiling and roof, or the ceiling and floor joists of the story above. The studs give the structure its vertical support, and the box-shaped floor sections with joists contained within length-long post and lintels (more commonly called headers), support the weight of whatever is above, including the next wall up and the roof above the top story. The platform also provides the lateral support against wind and holds the stick walls true and square. A lower platform can support the weight of platforms and walls above the level of its component headers and joists.
Exterior wall studs are the vertical members to which sheathing and cladding are attached. They are supported on a bottom plate or foundation sill and in turn support the top plate. Studs are commonly spaced at 16 inches on center. This spacing may be changed, e.g., to 12 or 24 inches on center, depending on the load and the limitations imposed by the type and thickness of the wall covering used. The studs are attached to horizontal top and bottom wall plates that are often the same width as the studs.
The floors, walls and roof of a building are typically made torsionally stable with the installation of a plywood or composite wood skin referred to as sheathing. Spacing the framing members properly usually allows them to align with the edges of standard sheathing. In the past, tongue and groove planks installed diagonally were used as sheathing. Occasionally, wooden or galvanized steel braces are used instead of sheathing. There are also engineered wood panels made for shear and bracing.
Some types of exterior sheathing, such as asphalt-impregnated fiberboard, plywood, oriented strand board and wafer board, may provide adequate bracing to resist lateral loads and keep the wall square. Construction codes in many jurisdictions require a stiff plywood sheathing. Others, such as rigid glass-fiber, asphalt-coated fiberboard, polystyrene or polyurethane board, will not. In these latter cases, walls have been reinforced with a diagonal wood or metal bracing inset into the studs. In jurisdictions subject to strong wind storms (hurricane countries, tornado alleys) local codes or state law may require both the diagonal wind braces and the stiff exterior sheathing, regardless of the type and kind of outer weather resistant coverings.
A multiple-stud post made up of at least three studs, or the equivalent, is generally used at exterior corners and intersections to secure a good tie between adjoining walls and to provide nailing support for the interior finish and exterior sheathing. Corners and intersections may be framed with at least two studs.
Roofs are usually built to provide a sloping surface intended to shed rain or snow, with slopes ranging from 1 cm of rise per 15 cm (less than an inch per linear foot) of rafter run (horizontal span), to steep slopes of more than 2 cm per cm (two feet per foot) of rafter run. The roof structure can be constructed from rafters and a ridge pole or now more commonly from pre-fabricated trusses that are assembled from stick members and metal connector plates to provide a ridged structure that is capable of extending over long spans without intermediate supports. A light-frame structure built mostly inside sloping walls comprising a roof is called an A-frame.
Light-frame methods allow easy construction of unique roof designs; hip roofs, for example, slope toward walls on all sides and are joined at hip rafters that span from corners to a ridge. Valleys are formed when two sloping roof sections drain toward each other. Dormers are small areas in which vertical walls interrupt a roof line, and which are topped off by slopes at usually right angles to a main roof section. Gables are formed when a length-wise section of sloping roof ends to form a triangular wall section.
Light-frame materials are most often wood or rectangular steel, tubes or C-channels. Wood pieces are typically connected with nails or screws as fasteners. Steel pieces may be connected with nuts and bolts. Preferred species for linear structural members are softwoods such as spruce, pine and fir. Recently, architects have begun experimenting with pre-cut modular aluminum framing to reduce on-site construction costs.
Intersections between portions of a framed building may be subject to shear. It has been known in the field of building construction to attach walls and floors to the building foundation in manner conducive to hold the building structure stable during hurricanes and/or earthquakes. As reflected above, construction systems intended for high wind (e.g., tornado or hurricane) prone or earthquake zones may require sufficient horizontal support from horizontal members, sheathing, and diagonal bracing in order to stabilize the structure. Metal ties may be used to connect frame components to the foundation. But currently there is no system which includes tying members spanning between sections of a building, between members along walls, between members around corners, members between levels, or the like to prevent damage due to shearing.